P. Ostrom | Geology Reports

USGS2008

Carbonate precipitation by the thermophilic archaeon Archaeoglobus fulgidus: A model of carbon flow for an ancient microorganism

Microbial carbonate precipitation experiments were conducted using the archaeon bacteria Archaeoglobus fulgidus to determine chemical and isotopic fractionation of organic and inorganic carbon into mineral phases. Carbonate precipitation was induced in two different experiments using A. fulgidus to determine the relative abundance of organically derived carbon incorporated into carbonate minerals as well as to define any distinct phases or patterns that could be attributed to the precipitation process. One experiment used a medium containing 13C-depleted organic carbon and 13C-enriched inorganic carbon, and the other used a 14C-labeled organic carbon source. Results indicated that 0.9 - 24.8% organic carbon was incorporated into carbonates precipitated by A. fulgidus and that this process was mediated primarily by pH and CO2 emission from cells. Data showed that the carbon in the CO2 produced from this microorganism is incorporated into carbonates and that the rate at which precipitation occurs and the dynamics of the carbonate precipitation process are strongly mediated by the specific steps involved in the biochemical process for lactate oxidation by A. fulgidus.

Biogeosciences Discussions↗

USGS1998

Foods of Buller's shearwaters (Puffinus bulleri) associated with driftnet fisheries in the central North Pacific Ocean

We examined digestive tract contents and stable nitrogen isotope ratios (??15N) in breast muscles of Buller's shearwaters (Puffinus bulleri) salvaged from squid and largemesh driftnets in the central North Pacific Ocean. The epipelagic Pacific saury (Cololabis saira) was the predominant prey, making up 71% of prey mass in digestive tracts. The remainder of the diet included small numbers of crustaceans, small fishes, and squids. The high degree of specialization in the diet seems to indicate that in the North Pacific, Buller's Shearwaters usually feed at or near the water surface and rarely pursue food under water. Although these birds have been observed feeding on scraps from fishing vessels, our data suggest that offal comprises less than 10% of the diet. Stable nitrogen isotope values provided quantified information on the timing of arrival of migrants into the North Pacific.

Notornis↗